These studies are designed to evaluate the clinical benefits achieved by iron chelation in patients with chronic iron overload. Desferrioxamine is administered by subcutaneous infusion and iron removal is determined by quantitation of urinary iron excretion and careful recording of the total iron administered by transfusion. The results of our 7 year study are summarized in this annual report. Briefly, we found that ascorbic acid given in low dose (3 mg/kg/day) had no significant affects on any measured parameters of iron metabolism nor was there any evident toxicity. Compliance with the chelation regimen was rather poor overall with older individuals in their teenage years showing significantly lower compliance than those in the first decade of life. A relationship between Desferal used and liver iron concentration was substantiated by study of 65 of our patients who had their liver iron concentration measured non-invasively. Efficacy of chelation therapy was not demonstrable in our experience, mainly because individuals with the highest risk for iron overload were among the least compliant in the study. We found that several non-invasive tests used over the past 7 years were not of great value in detecting subclinical iron toxicity. Therefore our followup protocol has been significantly simplified. The study will continue in an effort to document the natural history of individuals with various degrees of compliance with desferrioxamine treatment.